"A statistical analysis shows that icons with less detail score better in terms of usability. It seems to be an easy truth: too much detail in icons confuses the users. So we wondered whether we could find any evidence for this truth in the data of our large scale test of the LibreOffice Icons."

I think no matter how much or little detail in an icon, what matters is if it scales well. If you scale a very detailed icon that is beautiful at 256px down to 32px and the result looks nothing like the original, you've failed.